Hi,

Something really strange.
I am restarting a black knight after renovation. It was working perfectly before.
The CPU does not boot because it does not get the 5vdc.

The connector J6 on power board outputs 12vdc and 5vdc when measured as no female connector is plugged.

When I seat the female connector and none of the 2 ends is plugged (cpu and driver) I still get 5vdc.

If I plug one end on the cpu, I get only 2,6vdc on the Cpu J2 and the Power J6. If I do the same with the driver, I get 0vdc.

I suspected the female J6 connector and replaced it with a trifurcon. No change.

What’s the problem?

Thanks fot your help.
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No idea ?

Ok, I will try with only the cpu connected.

No problem, I can change the male connector on the power board, reflow solder

Thanks for the help

I have changed all electrolytic capacitors on the PB. Replaced the 5v regulator.

Removed the driver.

I only connect the power and the ground rectangle connectors on the PB. Then J6 on the PB to J2 on the CPU

Get no 5v.
If I take the voltage on the connector when not connected to the CPU, I get the 5v. Reflowed the solder on both male connectors.

Still stuck

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Even if the cpu does not start, I should get the 5v on j2

Continuity between the power board tracks (onboard) and tp9

Bridge rectifiers are new. Could the 30000 uf capacitor be responsible ?

Continuity is all right no problem with that.

How could the regulator fail if it gives the good values with no connection ?

I ll do so. I ll change the regulator. Please wait for 10 days before a further feedback. Going to Avignon on holiday.

In advance, many thanks to you my friends. Hope you will be there when I give the feedback

The lm323k was indeed the problem. Despite of a newly replaced regulator.

I had a few spare parts in a box, and I tried today.

Thanks for the help